1. Field of the Invention
The present invention relates to a method for forming ultranarrow metallic lines on a substrate and more particularly to the formation of ultra-narrow metallic lines using ion-implantation and etching techniques and wherein the resulting lines can have superconductive properties.
2. Description of the Prior Art
Techniques have been described for forming narrow lines, composed of polysilicon, using doping and etching techniques. A publication in the New Scientist, Sept. 25, 1975 on page 707 discusses a technique wherein polysilicon rather than metal is masked and doped with boron by diffusion. The masking layer is removed followed by removal of the undoped region of polysilicon by selective etching to leave the fine boron doped line.
The fact that ion implantation of certain impurities enhances the superconductivity of selected transition metals is also known, and is described in chapter 69 of the publication by O. Meyer entitled Ion Implantation in Superconductors in New Uses of Ion Accelerators, Ed. by J. F. Ziegler, Plenum Press, New York 1975.
The method of the present invention is distinct from the prior art in that the unobvious step of ion-implanting metal is used, providing both enhanced superconductivity and resistance to etching in a single processing operation so that ultra-narrow lines that also have superconductive properties can be fabricated.